Wondering- Are there "typical" file, export types within Illustrator, PhotoShop or InDesign? For example.. I was trying to save an autocad file as an eps.. I could NOT save in any other format than various AC versions but, within the "Export" menu, I was able to save as a WMF file which I was THEN able to open in Illustrator and THEN able to save as an EPS. Are there typical file types that can be created via SAVE AS -vs- EXPORT? if so.. what are the key attibutes of a file that determines weather it would need to be eported or saved as?

Also, is there any file type relation chart that I can refer to that will help me understand which files will compensate or assist eachother??

Thanks!